An expanding literature detailing the effects of major life events, and daily stressors on behavior, cognition and physiology attests to the importance of stressors in our everyday environment. Psychologists have focussed considerable attention on group differences in stress responses, but much less on individual differences in responsivity. However, both the physical nature of a stressor, as well as an individual's construal of psychologically-relevant events play an important role in determining the individual's response. This proposal describes a new methodology for assessing individual differences in the construal of psychological stressors and the effect of those stressors on physiology. These studies will examine individually determined stimulus-response functions relating the construal of stimuli differing in intensity to changes in cardiovascular reactivity. The proposed studies will examine the shape and parameters describing the stimulus-response functions for each individual. This strategy will be applied to the specific problem of assessing individual differences in the cardiovascular component of the stress response because individual variation in cardiovascular reactivity has been hypothesized to relate to both psychological and physical health. For example, both panic disorder and generalized anxiety disorder are associated with altered cardiovascular function. The role of individual differences in these and other anxiety disorders is receiving renewed interest because recently developed methods are beginning to provide a better understanding of the autonomic nervous system mechanisms underlying altered cardiovascular reactivity. Individuals with exaggerated cardiovascular reactivity have also been hypothesized to have an increased risk of hypertension or coronary artery disease, although the support for this hypothesis is mixed. Both of these types of studies require good methodological approaches for understanding individual differences in psychological and physical health. Thus, the proposed studies will examine physiological and affective responses to common laboratory-based psychological stimuli, the cold forehead and cold hand pressor tests, across a range of stimulus intensities. The cardiovascular responses will be plotted as functions of the construals of stimulus intensity, and the resulting functions will provide parameters for each individual. The results will permit an assessment of the usefulness of the proposed approach, the reliability of the individual parameters, and determine the relationship between an individual's construal of a psychologically- relevant event and his or her cardiovascular reactivity to that event.